The purpose of this study is to determine the safety and tolerance of different doses of rhIL-12, which will be given under the skin by injection; (2) To look at whether rhIL-12 might increase the body's ability to fight infections caused by certain disease-causing organisms like Mycobacterium avium bacteria, which causes a disease known as Mycobacterium avium complex (MAC). IL-12 is a type of protein that is naturally produced by certain types of cells of the immune system and is believed to be important for immune function. Although rhIL-12 has no direct effect against HIV. rhIL-12 may improve the ability of the immune system to fight the virus.